extra tweak from @huydhn

Author: swolchok

CMakeLists.txt

@@ -614,6 +614,8 @@ if(BUILD_EXECUTORCH_PORTABLE_OPS)
 endif()
 
 if(EXECUTORCH_BUILD_KERNELS_OPTIMIZED)
+  # find pytorch lib here to make it available to all sub-directories
+  find_package_torch_headers()
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/kernels/optimized)
 endif()
 

kernels/optimized/CMakeLists.txt

@@ -61,7 +61,6 @@ message("Generated files ${gen_command_sources}")
 
 list(TRANSFORM _optimized_kernels__srcs PREPEND "${EXECUTORCH_ROOT}/")
 add_library(optimized_kernels ${_optimized_kernels__srcs})
-find_package_torch_headers()
 target_include_directories(optimized_kernels PRIVATE ${TORCH_INCLUDE_DIRS} "${EXECUTORCH_ROOT}/third-party/pocketfft")
 target_link_libraries(
   optimized_kernels PRIVATE executorch_core cpublas extension_threadpool